VRT and full page cache

Thanks reaching out!

You’re correct. When using a full-page cache, the plugin will test against the cached version of your site. This means that if changes are made to the live site but the cache hasn’t been updated, the plugin will not detect these changes until the cache clears. This behavior is expected because website visitors would also be viewing the cached version of the page.

As you said, some caching plugins offer a way to bypass the cache by attaching a get parameter to the URL or using cookies. However, our VRTs plugin currently does not provide the capability to attach parameters or cookies to requests. The URLs are registered and called with a task scheduler service running on a separate infrastructure. The URLs submitted to the service could be programmatically altered, but I strongly advise against that as this might lead to unexpected results.

To do it well, we would need to implement the feature on the remote service with a control option in the plugin. I have noted this as a feature request.

In the meantime, if your caching solution offers manual cache clearing, you might consider doing that before running the visual regression tests to ensure you’re testing the most recent version of your site.

I hope this helps. Please don’t hesitate to reach out if you have further questions or need any assistance.

Thanks @steffenbew for your detailed response.

BTW, I thought everything related to the plugin is self-hosted, but I now understand there is an external service that crawls the website?

Thanks again.

You’re welcome!

We would have liked the plugin to do everything self-hosted, but decided against it for the following reasons:

1. Taking screenshots requires special tools to be installed on a server, like a headless browser. Most website servers don’t have such tools installed and available.
2. Taking screenshots is resource intense and could endanger a websites availability.
3. Saving screenshots requires significant space, which might result in extra server requirements and costs.

That’s why we take the screenshots on an external server. We documented this in the FAQ section of the plugin details:

Is the testing done on my server?
Screenshots and comparisons are performed on an external server and sent to your WordPress website. Only required meta data is stored in your database.

• This reply was modified 1 year, 4 months ago by steffenbew.
• This reply was modified 1 year, 4 months ago by steffenbew. Reason: formatting

Thanks again for the explanation.